From 237ef567f6764f24a47c63121cc0a599ddc8f56d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 31 Aug 2003 19:10:30 +0000 Subject: [PATCH] Heavily refactor code: * Separate the policy decisions into a derived class [InlineSimple] * Move the inlining mechanics into a base class [Inliner] * Change the inliner to be an SCCPass, making it more structured and eventually pipelinable with other SCC passes git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8257 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/IPO/InlineSimple.cpp | 154 +++++----------------------- lib/Transforms/IPO/Inliner.cpp | 119 +++++++++++++++++++++ lib/Transforms/IPO/Inliner.h | 52 ++++++++++ 3 files changed, 198 insertions(+), 127 deletions(-) create mode 100644 lib/Transforms/IPO/Inliner.cpp create mode 100644 lib/Transforms/IPO/Inliner.h diff --git a/lib/Transforms/IPO/InlineSimple.cpp b/lib/Transforms/IPO/InlineSimple.cpp index 64a210d30f3..e62a8b13445 100644 --- a/lib/Transforms/IPO/InlineSimple.cpp +++ b/lib/Transforms/IPO/InlineSimple.cpp @@ -1,77 +1,47 @@ -//===- FunctionInlining.cpp - Code to perform function inlining -----------===// +//===- InlineSimple.cpp - Code to perform simple function inlining --------===// // // This file implements bottom-up inlining of functions into callees. // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "inline" -#include "llvm/Transforms/IPO.h" -#include "llvm/Module.h" -#include "llvm/Pass.h" -#include "llvm/iOther.h" +#include "Inliner.h" +#include "llvm/Function.h" #include "llvm/iMemory.h" -#include "llvm/iTerminators.h" #include "llvm/Support/CallSite.h" -#include "llvm/Transforms/Utils/Cloning.h" -#include "Support/CommandLine.h" -#include "Support/Debug.h" -#include "Support/Statistic.h" -#include +#include "llvm/Transforms/IPO.h" namespace { - Statistic<> NumInlined("inline", "Number of functions inlined"); - Statistic<> NumDeleted("inline", "Number of functions deleted because all callers found"); - cl::opt // FIXME: 200 is VERY conservative - InlineLimit("inline-threshold", cl::Hidden, cl::init(200), - cl::desc("Control the amount of inlining to perform (default = 200)")); - - struct FunctionInlining : public Pass { - virtual bool run(Module &M) { - bool Changed = false; - for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) - Changed |= doInlining(I); - ProcessedFunctions.clear(); - return Changed; - } - - private: - std::set ProcessedFunctions; // Prevent infinite recursion - bool doInlining(Function *F); + struct SimpleInliner : public Inliner { + int getInlineCost(CallSite CS); }; - RegisterOpt X("inline", "Function Integration/Inlining"); + RegisterOpt X("inline", "Function Integration/Inlining"); } -Pass *createFunctionInliningPass() { return new FunctionInlining(); } +Pass *createFunctionInliningPass() { return new SimpleInliner(); } -// ShouldInlineFunction - The heuristic used to determine if we should inline -// the function call or not. +// getInlineCost - The heuristic used to determine if we should inline the +// function call or not. // -static inline bool ShouldInlineFunction(CallSite CS) { +int SimpleInliner::getInlineCost(CallSite CS) { Instruction *TheCall = CS.getInstruction(); - assert(TheCall->getParent() && TheCall->getParent()->getParent() && - "Call not embedded into a function!"); - const Function *Callee = CS.getCalledFunction(); - if (Callee == 0 || Callee->isExternal()) - return false; // Cannot inline an indirect call... or external function. - - // Don't inline a recursive call. const Function *Caller = TheCall->getParent()->getParent(); - if (Caller == Callee) return false; - // InlineQuality - This value measures how good of an inline candidate this - // call site is to inline. The initial value determines how aggressive the - // inliner is. If this value is negative after the final computation, - // inlining is not performed. + // Don't inline a directly recursive call. + if (Caller == Callee) return 2000000000; + + // InlineCost - This value measures how good of an inline candidate this call + // site is to inline. A lower inline cost make is more likely for the call to + // be inlined. This value may go negative. // - int InlineQuality = InlineLimit; + int InlineCost = 0; // If there is only one call of the function, and it has internal linkage, // make it almost guaranteed to be inlined. // if (Callee->use_size() == 1 && Callee->hasInternalLinkage()) - InlineQuality += 30000; + InlineCost -= 30000; // Add to the inline quality for properties that make the call valueable to // inline. This includes factors that indicate that the result of inlining @@ -83,12 +53,12 @@ static inline bool ShouldInlineFunction(CallSite CS) { // Each argument passed in has a cost at both the caller and the callee // sides. This favors functions that take many arguments over functions // that take few arguments. - InlineQuality += 20; + InlineCost -= 20; // If this is a function being passed in, it is very likely that we will be // able to turn an indirect function call into a direct function call. if (isa(I)) - InlineQuality += 100; + InlineCost -= 100; // If a constant, global variable or alloca is passed in, inlining this // function is likely to allow significant future optimization possibilities @@ -96,7 +66,7 @@ static inline bool ShouldInlineFunction(CallSite CS) { // the inlining of the function. // else if (isa(I) || isa(I) || isa(I)) - InlineQuality += 60; + InlineCost -= 60; } // Now that we have considered all of the factors that make the call site more @@ -106,84 +76,14 @@ static inline bool ShouldInlineFunction(CallSite CS) { // Look at the size of the callee. Each basic block counts as 20 units, and // each instruction counts as 10. for (Function::const_iterator BB = Callee->begin(), E = Callee->end(); - BB != E; ++BB) { - InlineQuality -= BB->size()*10 + 20; - if (InlineQuality < 0) return false; - } + BB != E; ++BB) + InlineCost += BB->size()*10 + 20; // Don't inline into something too big, which would make it bigger. Here, we // count each basic block as a single unit. for (Function::const_iterator BB = Caller->begin(), E = Caller->end(); - BB != E; ++BB) { - --InlineQuality; - if (InlineQuality < 0) return false; - } + BB != E; ++BB) + InlineCost++; - // If we get here, this call site is high enough "quality" to inline. - DEBUG(std::cerr << "Inlining in '" << Caller->getName() - << "', quality = " << InlineQuality << ": " << *TheCall); - return true; + return InlineCost; } - - -// doInlining - Use a heuristic based approach to inline functions that seem to -// look good. -// -bool FunctionInlining::doInlining(Function *F) { - // If we have already processed this function (ie, it is recursive) don't - // revisit. - std::set::iterator PFI = ProcessedFunctions.lower_bound(F); - if (PFI != ProcessedFunctions.end() && *PFI == F) return false; - - // Insert the function in the set so it doesn't get revisited. - ProcessedFunctions.insert(PFI, F); - - bool Changed = false; - for (Function::iterator BB = F->begin(); BB != F->end(); ++BB) - for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) { - bool ShouldInc = true; - // Found a call or invoke instruction? - if (isa(I) || isa(I)) { - CallSite CS = CallSite::get(I); - if (Function *Callee = CS.getCalledFunction()) { - doInlining(Callee); // Inline in callees before callers! - - // Decide whether we should inline this function... - if (ShouldInlineFunction(CS)) { - // Save an iterator to the instruction before the call if it exists, - // otherwise get an iterator at the end of the block... because the - // call will be destroyed. - // - BasicBlock::iterator SI; - if (I != BB->begin()) { - SI = I; --SI; // Instruction before the call... - } else { - SI = BB->end(); - } - - // Attempt to inline the function... - if (InlineFunction(CS)) { - ++NumInlined; - Changed = true; - // Move to instruction before the call... - I = (SI == BB->end()) ? BB->begin() : SI; - ShouldInc = false; // Don't increment iterator until next time - - // If we inlined the last possible call site to the function, - // delete the function body now. - if (Callee->use_empty() && - (Callee->hasInternalLinkage()||Callee->hasLinkOnceLinkage())){ - F->getParent()->getFunctionList().erase(Callee); - ++NumDeleted; - if (Callee == F) return true; - } - } - } - } - } - if (ShouldInc) ++I; - } - - return Changed; -} - diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp new file mode 100644 index 00000000000..7f75f1453fc --- /dev/null +++ b/lib/Transforms/IPO/Inliner.cpp @@ -0,0 +1,119 @@ +//===- InlineCommon.cpp - Code common to all inliners ---------------------===// +// +// This file implements the code shared between the LLVM inliners. This +// implements all of the boring mechanics of the bottom-up inlining. +// +//===----------------------------------------------------------------------===// + +#include "Inliner.h" +#include "llvm/Module.h" +#include "llvm/iOther.h" +#include "llvm/iTerminators.h" +#include "llvm/Analysis/CallGraph.h" +#include "llvm/Support/CallSite.h" +#include "llvm/Transforms/Utils/Cloning.h" +#include "Support/CommandLine.h" +#include "Support/Debug.h" +#include "Support/Statistic.h" + +namespace { + Statistic<> NumInlined("inline", "Number of functions inlined"); + Statistic<> NumDeleted("inline", "Number of functions deleted because all callers found"); + cl::opt // FIXME: 200 is VERY conservative + InlineLimit("inline-threshold", cl::Hidden, cl::init(200), + cl::desc("Control the amount of inlining to perform (default = 200)")); +} + +Inliner::Inliner() : InlineThreshold(InlineLimit) {} + +int Inliner::getRecursiveInlineCost(CallSite CS) { + return getInlineCost(CS); +} + +bool Inliner::runOnSCC(const std::vector &SCC) { + CallGraph &CG = getAnalysis(); + + std::set SCCFunctions; + DEBUG(std::cerr << "Inliner visiting SCC:"); + for (unsigned i = 0, e = SCC.size(); i != e; ++i) { + SCCFunctions.insert(SCC[i]->getFunction()); + DEBUG(std::cerr << " " << (SCC[i]->getFunction() ? + SCC[i]->getFunction()->getName() : "INDIRECTNODE")); + } + DEBUG(std::cerr << "\n"); + + bool Changed = false; + for (std::set::iterator SCCI = SCCFunctions.begin(), + E = SCCFunctions.end(); SCCI != E; ++SCCI) { + Function *F = *SCCI; + if (F == 0 || F->isExternal()) continue; + DEBUG(std::cerr << " Inspecting function: " << F->getName() << "\n"); + + for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) + for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) { + bool ShouldInc = true; + // Found a call or invoke instruction? + if (isa(I) || isa(I)) { + CallSite CS = CallSite::get(I); + if (Function *Callee = CS.getCalledFunction()) + if (!Callee->isExternal()) { + // Determine whether this is a function IN the SCC... + bool inSCC = SCCFunctions.count(Callee); + + // If the policy determines that we should inline this function, + // try to do so... + int InlineCost = inSCC ? getRecursiveInlineCost(CS) : + getInlineCost(CS); + if (InlineCost < (int)InlineThreshold) { + DEBUG(std::cerr << " Inlining: cost=" << InlineCost + << ", Call: " << *CS.getInstruction()); + + // Save an iterator to the instruction before the call if it + // exists, otherwise get an iterator at the end of the + // block... because the call will be destroyed. + // + BasicBlock::iterator SI; + if (I != BB->begin()) { + SI = I; --SI; // Instruction before the call... + } else { + SI = BB->end(); + } + + if (performInlining(CS, SCCFunctions)) { + // Move to instruction before the call... + I = (SI == BB->end()) ? BB->begin() : SI; + ShouldInc = false; // Don't increment iterator until next time + Changed = true; + } + } + } + } + if (ShouldInc) ++I; + } + } + return Changed; +} + +bool Inliner::performInlining(CallSite CS, std::set &SCC) { + Function *Callee = CS.getCalledFunction(); + Function *Caller = CS.getInstruction()->getParent()->getParent(); + + // Attempt to inline the function... + if (!InlineFunction(CS)) return false; + ++NumInlined; + + // If we inlined the last possible call site to the function, + // delete the function body now. + if (Callee->use_empty() && Callee != Caller && + (Callee->hasInternalLinkage() || Callee->hasLinkOnceLinkage())) { + DEBUG(std::cerr << " -> Deleting dead function: " + << Callee->getName() << "\n"); + std::set::iterator I = SCC.find(Callee); + if (I != SCC.end()) // Remove function from this SCC... + SCC.erase(I); + + Callee->getParent()->getFunctionList().erase(Callee); + ++NumDeleted; + } + return true; +} diff --git a/lib/Transforms/IPO/Inliner.h b/lib/Transforms/IPO/Inliner.h new file mode 100644 index 00000000000..a6422951cee --- /dev/null +++ b/lib/Transforms/IPO/Inliner.h @@ -0,0 +1,52 @@ +//===- InlineCommon.h - Code common to all inliners -------------*- C++ -*-===// +// +// This file defines a simple policy-based bottom-up inliner. This file +// implements all of the boring mechanics of the bottom-up inlining, while the +// subclass determines WHAT to inline, which is the much more interesting +// component. +// +//===----------------------------------------------------------------------===// + +#ifndef INLINER_H +#define INLINER_H + +#define DEBUG_TYPE "inline" +#include "llvm/CallGraphSCCPass.h" +#include +class CallSite; + +/// Inliner - This class contains all of the helper code which is used to +/// perform the inlining operations that does not depend on the policy. +/// +struct Inliner : public CallGraphSCCPass { + Inliner(); + + // Main run interface method, this implements the interface required by the + // Pass class. + virtual bool runOnSCC(const std::vector &SCC); + + /// This method returns the value specified by the -inline-threshold value, + /// specified on the command line. This is typically not directly needed. + /// + unsigned getInlineThreshold() const { return InlineThreshold; } + + /// getInlineCost - This method must be implemented by the subclass to + /// determine the cost of inlining the specified call site. If the cost + /// returned is greater than the current inline threshold, the call site is + /// not inlined. + /// + virtual int getInlineCost(CallSite CS) = 0; + + /// getRecursiveInlineCost - This method can be implemented by subclasses if + /// it wants to treat calls to functions within the current SCC specially. If + /// this method is not overloaded, it just chains to getInlineCost(). + /// + virtual int getRecursiveInlineCost(CallSite CS); + +private: + unsigned InlineThreshold; + bool performInlining(CallSite CS, std::set &SCC); +}; + + +#endif